Flexible cope



June 27, 1939; c. HANSEN 2 ,163,681

FLEXIBLE COPE Filed Oct. 25, 1957 2 Sheets-Sheet 1 E j" /7 I g q ia-E-INVENTOR.

CHE/J A. H/mmE/v .4 TTORXE) June 27, 1939. Q HANSEN 2,163,681

FLEXIBLE corn Filed Oct. 25, 1937 2 Sheets-Sheet 2 INVENTOR.

.2 T IE 4C C 2/6 K HAMJEN A TTORNE Y.

Patented June 27, 1939 UNITED STATES PATENT OFFICE 1 Claim.

This invention relates to improvements in false copes such as used inthe making of sand molds for casting metal in foundries.

In the present practice of casting metal the molten metal is poured intosand molds which have a cavity of the shape of the desired cast articleand so that this metal fills the cavity and hardens therein to form thearticle after which the mold may be removed. The mold comprises twosections called the drag or bottom and the cope or top and thesesections have in their meeting faces the impressions or recesses whichtogether form the casting cavity of the desired shape and size. Theseimpressions are formed by laying the pattern, which is of the same shapeand size as the desired finished article, in an enclosing box or housingcalled a flask, blocking up the pattern so that it stands clear of thebottom of the flask and then sprinkling the molding sand into the flaskso that it covers the pattern. The sand is then rammed and packed hard,the blocking removed, and the sand cut away in a flat plane down to amedial point of the pattern. This point of the pattern is called theparting line and must be determined according to the shape of thepattern so that no lateral projections thereof below the parting linewill prevent drawing the pattern from the mold. The parting line or faceof the mold is then smoothed with a suitable tool and this completes thedrag or bottom section of the mold. A fine dust of suitablecharacteristics is then sprinkled over the face of the drag and theexposed part of the pattern. Sand is then placed in the flask and rammedsolidly against the drag after which, by removing the flask, this topsection of the mold called the cope may be removed and, due to theaction of the dust aforesaid, will separate nicely from the drag alongthe parting line. The pattern may then be removed and when the drag andcope are placed together a cavity remains of the same shape and size asthe pattern. This cavity may then be filled with the molten metalthrough what is called the sprue and when the metal hardens the castingmay be removed and will be of the desired shape and size. The spruereferred to is a small hole formed in the cope of the mold and leadinginto the cavity therein or into gates which lead to other cavities wheremore than one article is cast in the same mold.

The foregoing process requires considerable time and labor as will beunderstood and in the attempt to reduce the time and labor of this kindof casting a false cope is used. This is in reality simply a cope madeof some relatively rigid material and is formed by placing this materialon the pattern and completed drag and applying pressure so that the copeis formed with a cavity matching the exposed parts of the casting. Withthe cope thus prepared both the drag and cope may be made up as neededwithout the laborious and time consuming operation of facingoif the dragto the parting line as hereinbefore described. This is made possible byfirst using the cope as a bottom section, placing it in the flask withthe pattern in the impression and packing the sand against the plate andpattern. This forms the drag of the mold and of course as the cope isremoved the parting line or face is left smooth and requires no tooling.Thereafter the cope is made in the usual manner against the drag and thework is carried out as described.

A great deal of difficulty has been experienced heretofore in making upthese copes due to the fact that no suitable material has been found forthis purpose. All materials now used have the extreme disadvantage ofbeing relatively frangible and friable. As a result the copes afterbeing used a short time begin to crumble and break away especiallyaround the edges of the pattern impressions therein and when used inthis condition the sand as it is packed in for the drag fills thesecrumbled portions. This sand then may remain on the drag when the copeis removed, may crumble and fall into the casting cavity, or may adhereto and be withdrawn with the pattern. When this excess of sand dropsinto the cavity it will of course form pits in the finished casting andwhen it crumbles away and is withdrawn with the pattern then it leaves aspace around the pattern at the parting line which fills with metal andresults in the formation of a fin or projection around the casting atthis point. A great number of castings are thus spoiled and must bediscarded while others require grinding and expensive finishing work tofit them for use.

With the foregoing facts in mind it is the primary object of myinvention to provide a false cope having sufficient resiliency toprevent the edges from crumbling or breaking off and thus to ensure asharp clean parting line at all times. By the use of false copes of thiskind a very substantial saving will result, this being due to the factthat the now prevalent scrapping of very rough castings will beeliminated and the labor and materials used in grinding off the fins ofthe castings will be greatly reduced.

Another object is to provide a false cope of this kind made up of atough, resilient and infrangible material such as will retain its shapeunder the pressure exerted against it as the sand is packed to form themold drag and which will resist wear and breakage due to rough handling.

Still a further object is to provide a resilient false cope of theforegoing characteristics having reinforcing and mounting means wherebyit will be given transverse and longitudinal rigidity and may be mountedin a frame to serve as a guide in its use in the flask.

The foregoing and other objects and advantages of the invention will bemade apparent in the course of the following detailed. specifications,reference being had therein to the accompanying drawings wherein:

Figure 1 is a plan or face view of a two-pattern false cope made inaccordance with this invention, a corner portion thereof being brokenaway to disclose the reinforcing and mountingmeans for the false cope. I

Figure 2 is an enlarged longitudinal and fragmental section along theirregular line 2-2 in Figure l, the pattern being shown therein.

Figure 3 is a longitudinal cross section through a false cope made inaccordance with this invention, showing the flask and a mold drag madeup against the false cope and the patterns therein.

Figure 4 is a longitudinal section through a flask and mold drag,showing a false cope being made therein in accordance with thisinvention, the patterns being in place and a steam pressure plate beingshown as in use in forming the false cope.

Referring now with more particularity to the drawings my improved falsecope is designated generally at 5 and is of flat rectangular shapehaving the two pattern impressions or recesses 6 and l in its partingface 8. Inthe instance shown the false cope has two pattern impressionsalthough any number of course may be used according to the nature of thearticle to be cast, and the patterns indicated at A and B are in theshape of, and designed to form, seed plates for corn planters. For thispurpose the patterns include the center boss C, the annular tapering rimD, the connecting spokes or arms E, the pin F and other small partswhich need not be referred to specifically since this form of pattern isshown only for purposes of exemplification. To accommodate thesepatterns, the false cope 5,

' 1 as stated, has the spaced impressions 5 and I with the sloping sides9' to accommodate the pattern rim D, the center socket or pocket if! toreceive the boss C and the radially extended grooves or valleys H toreceive the spokes E so that the patterns will seat in the impressionsdown to the parting lines G on the pattern. It will be noted that abovethe parting lines G no part of the patterns project so as to form anobstruction to prevent drawing the sand drag from the false cope (aswill be described) and the parting line is in all cases so located onthe pattern that this condition will obtain.

In making the false cope the mold drag is prepared in the usual mannerby blocking up the patterns A and B in the flask, packing the moldingsand in the flask around the patterns and then facing off the sand downto the parting lines G. This drag, indicated at H in Figure 4, is thenplaced on a metal plate I, confined within a rectangular upstanding bandor frame J which extends above the face of the drag some distance andplaced in an oven and baked until hard. The parting face K of the dragis then filled in with plaster of Paris or other suitable material so asto be perfectly smooth, the patterns A and B are replaced, and thecomposition or material used for the match plate is filled in within theband J. A hollow pressure pad or steam casting L is then pressed down onthe material within the band J by action of the screw jack M and steamis passed through the pad to melt or soften the packed material causingit to flow around all parts of the patterns and become a compactedhomogeneous mass. The pad L is then removed, the false cope allowed tocure and then removed ready for use. The exposed faces of the drag 4,patterns A and B and surrounding band J are all initially coated withsome non-vulcanizing or non-melting material such as plaster of Paris tofacilitate the removal of the finished plate.

The material or compositions used for the false cope may be rubberscraps or other suitable resilient tough matter of low melting point andin the process of filling in over the patterns a sheet i 2 ofreinforcing screen or mesh is placed so as to clear the patterns A and Band lie within the body of the completed cope. This sheet if: serves toreinforcethe cope as a whole against flexing motion either transverselyor longitudinally and permits the use of comparatively coarse.

or cheap material for the body or back portion of the cope. The materialused for the face of the cope however should be of a finer nature so asto present a smooth surface and have the necessary wear resistant andresilient qualities. To provide for mounting the finished plate washersl3 are placed around the corners and near the center line of thereinforcing plate 12 and pins I are placed in the drag H so that theywill project upwardly through these washers and will form screw holes 15through the finished cope as will be clearly evident.

When removed from the band J the false cope is mounted on a rectangularboard I6 by screws i'i passed through the holes l5 and washers 13 intothe board and the margins are confined within a frame H3 in the mannershown. This frame l8 carries projecting handles 19 which have guideapertures as. In use then the cope thus mounted receives the patterns Aand B in its impressions 6 and T and the flask top N is placed over thecope with the guide pins 0 through the apertures 20 after which the moldsand is rammed down into the flask to form additional mold drags 64 asrequired (Figure 3). When the false cope is removed it will be evidentthat the parting face of the drag will be left smooth and clear readyfor making the cope (not shown) without any smoothing or tooling of anykind.

From the foregoing it will be apparent that I have provided a false copewhich may be readily made up as required and which is of such resilientcharacteristics that it will retain its shape at all times and will notcrumble or break away around the pattern impressions as so often occurswith other materials. The disadvantages resulting from this crumbling ofthe false cope have been pointed out hereinbefore and need no further description herein. The material used for the false cope should have aboutthe same resiliency and hardness as the casing of an ordinary automobiletire, this being found to afford sufficient resiliency to preventbreaking off the edges of the pattern impressions while still making thefalse cope solid enough to prevent distortion when under pressure of thesand as it is packed to make the mold drag.

While I have herein set forth a certain preferred embodiment of myinvention it is under stood that'I may vary from the same in details i5Within the scope of the appended claim. Having thus fully illustratedand described my invention, what I claim is new and desire to secure byLetters Patent is:

A false cope for making casting molds from patterns, the said cope beingmade of rubber heated and flowed around. a pattern for forming a patternimpression in one face of the cope while leaving the opposite faceplane, a sheet of ree inforcing material imbedded in the cope parallelwith the plane face thereof, and the portion of the cope around thepattern impression being formed of rubber of fine texture while theportion strengthened by the reinforcing sheet is formed of a coarse andcrude rubber.

CHRIS K. HANSEN.

